To study our CIP, we derive first a constructive proof of an existence and
uniqueness theorem for the forward problem for RRTE. An important assertion
of this theorem, which is significantly used for our numerical method for
the CIP, is the claim about the positivity of the solution of the forward
problem. Previously this positivity was proven only for the case of RTE in
[1]}. From the numerical prospective, this theorem allows us to solve
RRTE numerically as a linear integral equation with integrals over geodesic
lines. We use this solution to computationally simulate the data for our
inverse problem. Other existence and uniqueness results for the forward
problems for RTE and RRTE, although without claims of the positivity of
solutions, can be found in [2]}, [3]}, [4]}. The form of RRTE in
[2]} is more general than the one of this paper.
